[scudo] Temporary disabling the valloc test on armhf

[cryptoad]

Summary

Weird failure where errno != ENOMEM on valloc failure. The returned pointer
is null since it passes the previous assert, so this shouldn't happen.

http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15-full/builds/10931
http://lab.llvm.org:8011/builders/clang-cmake-thumbv7-a15-full-sh/builds/2469

Disabling until we figure out what's going on.

test/scudo/valloc.cpp

 // RUN: %clang_scudo %s -o %t
 // RUN:                                                 %run %t valid   2>&1
 // RUN:                                             not %run %t invalid 2>&1
 // RUN: %env_scudo_opts=allocator_may_return_null=1     %run %t invalid 2>&1
-// UNSUPPORTED: android
+// UNSUPPORTED: android, armhf-linux
 
 // Tests that valloc and pvalloc work as intended.
 
 #include <assert.h>
 #include <errno.h>
 #include <malloc.h>
 #include <stdint.h>
 #include <string.h>